Buffing disk



Nv.25, 1941. f F,W .VERMQNT f 2,263,883

BUFFING DISK f Filed Feb. 5, 1940 2 Sheets-Sheet l INVENTOR.

ATTORNEY.

Nov. 25, 1941.

F. w. LIVERMONT l2,263,883

BUFFING DISK Filed Feb. 5, 1940 2v Sheets-Sheet 2 ATTORNEY.

Patented Nov. 25, 1941 UNITED STATES PATENT OFFICE'- BUFFING DISK Frank W. Livermont, Glendale, Calif, Application February 5, 1940, Serial No. 317,250

Y (o1. ie-zso) 6 Claims.

This invention is a rotatable bufling disk having a pile face dening a surface adapted for bung contact with thework.

It is an object of the invention to insure substantially uniform wear throughout the area of the pile face of the disk, for prolonging the usefulness of the bu'ing disk.

It is a further object of the invention to brace the strands of the pile against radially outward tilting responsive to centrifugal force generated by rotation of the disc. The surface defined by the outer ends of the strands is thus a substantially plane surface adapted for substantially uniform bufng contact and consequent uniform wear throughout its area.

It is a still further object of the invention to balance the disc for rotation in a plane perpendicular to its axis, for uniform bufling contact and consequent uniform wear-throughout the area of the buing surface which is defined by the pile.

Further objects of the invention will be readily understood from the following description of the accompanying drawings, in which:

Fig. 1 is a front elevation of the buftlng disk.

Fig. 2 is a side elevation of the same, partly in axial section.

Fig. 3 is a front elevation of a bufIing disk, showing a modied construction.

Fig. 4 is a side elevation of this modified construction, partly in axial section.

Bufling disks comprise a flexible backing I having a heavy pile face. The disk is detachably clamped at its axis onV a spindle 2 as shown at IIJ, with the spindle and the disk adapted for rotation by means (not shown) which is preferably a power-driven hand tool whereby the operator may contact the work by the heavy pile face of the rapidly rotating disc. The exible backing I is preferably a relatively heavy woven fabric, and the pile face comprises strands 3 which are looped through and project from the fabric backing so that the outer ends of the strands define the buii'ing surface.

The strands 3 are of uniform length so that when in normal position projecting perpendicularly from the backing I, the bung surface 4" which is defined by the outer ends of the strands is a plane surface parallel to the plane of the backing I. heretofore constructed, the strands 3 have been radially outwardly tilted responsive to centrifugal force generated by rapidly rotating the disk, with this distortion increasing toward the outer periphery of the disc. 'Ihe buing surface of the When employing buing disks as rotating disc has thus beendistorted from the plane surface 4 to the curved surface 4a. Consequently, contact of the bufling surface with the work has resulted in greater wear at its radially inner portion than at its radially outer portion, and this uneven wear has appreciably shortened the period of usefulness ofthe bufling disc.

In the present invention, the strands 3 are braced against radially outward distortion responsive to centrifugal force, so that they remain substantially perpendicular to the backing I, thereby maintaining their buing surface in substantially the plane 4 for substantially uniform wear throughout the area of this bufling surface. Y

As an instance, and as shown at Figs. 1 and 2, the strands 3 which are adjacent the outer periphery of the backing I are bent down against the face of the backing and radially toward its axis, along relatively short portions of the inner ends of the strands where they first project from the backing, with the remainder of the length of these strands projecting outwardly from the face of the backing. The portions of the strands which are bent radially toward the axis of the` backing are shown at 3a, and the portions of these strands which project outwardly from the face of the backing are shown at 3b. The strands 3a-3b Aare secured in their bent position by stitching through the bentfstrands and the backing around the circumference of the buifing disk and in radially spaced relation from its periphery as shown at 5, so that therstitching extends through the bent strands at the junction of their portions Sat-3b. The stitching 5 is spaced a relatively short distance fromV the outer periphery of the buflng disk, so that the strands 3w-3bthrough which the stitching extends are only the last few of the looped strands which are adjacent the outer periphery of the buiingdisk and so that the portions 3a of these bent strands are relatively short portions of the entire length of these strands.

By thus stitching the bent strands to the backing I, they are transversely compressed at the junction of their portions 3ft-3b; and this compression area forms a brace for the remaining strands 3 which project from the major portion of the area of the backing I, thereby bracing the strands 3 against radially outward tilting responsive to centrifugal force generated by the rapidly rotating bumng disc.

This compression area of the strands `3a-3b is immediately adjacent the outer face of the backing I, so that the strands 3 are radially braced adjacent their inner ends while their outer ends are free of transverse compression and thus form a usual yieldable buning surface 4 in appreciable longitudinally spaced relation from the compression area of the strands 3a3b. The bung surface being thus longitudinally spaced from the compression area, is adapted for usual yieldable bufling contact with the workfwithout the compression area producing such a nonyielding peripheral portion of the bufling surface as would ring the buried area of the work.

By bracing the strands 3 against radial distortion, they project substantially perpendicularly from the backing I and the bufiing surface which they form is thus a substantially plane surface 4 which is parallel to the backing I, rather than a curved surface 4a such as would result, if the strands 3 were not braced against radial distortion. The buing surface, being a plane surface, is thus adapted for substantially uniform wear throughout its area, for prolonging the pe- 'riod of, usefulness ofthe buflirlg disk.'

This buiiing surface is coextensive with the area of the backing I except as this bufing area is reduced by the area `occupied by the strands b, but the areaY occupied by these strands is so small in comparison with the area` defined byV the strands ,3, as to be negligible when considering the effective area of the buiiing disk.

At Figs. 3 and 4, a modied construction is shown. In this instance, the bentstrands 3a3b are kheld in place not by stitching such as previously described, but by a clamping annulus which overlies the portions 3a of these strands for clamping them against the backing I, with the 'portions 3b of the strands curving around the inner periphery of the clamping annulus and then projecting outwardly from the backing I, thereby forming a compression area atthe junction of the portions4 3cr-3b. of the strands for bracing lthe strands,A 3 against radial distortion as previously described. v The clamping yannulus may be a channeled peripheralportion 1 of a, disk 8 which overlies the rear face of the backing I and `is clamped at its axis to the spindle 2 by the same clamping means I 8 which holds the bufngdisk in place. The clamping annulus I fits over the periphery of the buing disk Vand, extends radiallyV inwardly substantially the same distance as that previously described in connection withr the stitching 5, whereby the same relatively few outer peripheral rows of the strands of the buing disk are bent as shown at 3ft-3b for radially bracing the major portion of the strands,- which are'shown at. 3'.

The disk 8l together with its channeled clampving annulus 1,v may be of a somewhat'flexible material permitting desired flexing of the backing l, but is of, such limited flexibility that the 21.11111- ius li maintains desired clamping engagement with the. .portionsaot the strands 3ft-3b', For this purpose, the disk 8 and its clamping annulus 1 may be an integral structure of relatively hard rubber..

,The clamping means lIl) longitudinally. compresses the pile of the bufiing disk at its axis so as, to clamp the disk to the spindle 2 with the plane yof clamping engagement in susbtantially the normalplane of the backing I as indicated lat I4 (Fig. 4). The plane of the center of gravity of the rotating disk, longitudinally of its axis, is therefore offset relative to the plane I4 as indicated for example at I5, due to the weight of theple which projects from only one face of the backing I.

When the flexible buing disk is rotated, there is consequently tendency toward distortion of the outer peripheral portion of the disk due to the plane I5 seeking alinement with the plane I4, thereby tending to curve the backing I as shown at I6 and thus tending to curve the bufling surface as shown at 4c. When such curvature of the buliing surface occurs, it results in nonuniform buing contact throughout its area, whether or not the means previously described has been employed for insuring a bung surface which is parallel to the backing I; and such nonuniform buffing contact causes uneven wear of the pile face of the buing disk, and thus shortens the period of usefulness of the disk.

Topreyent this distortion of the bufling disk, it may be balanced so that even though the weight of its projecting pile is at only one face of the disk, the plane of its center of gravity, longitudinally of `the axis of rotation, is in alinement with theplane of the clamping engagement between the disk audits spindle.

As an instance, counterweight is provided at that face of the backing I which is opposite its projecting pile, kso 'as to balance the projecting pile and thus place the center of gravity, longitudinally of the axis 0f rotation, in the normal plane of the backing I, i. e. in the vplane of clampingengagement'between the buflingl disk and its spindle'.

This counterweight at the rear face of the backing AI may be provided in various ways, the construction` which is illustrated at Figs. 3 and 4 showing a preferred means. In this construction, the counterweightis provided by the disk 8 which overlies` the rear face of the bufng disk. The major portion of the counterweight is preierably toward the outer periphery of the rotatable structure where there is the greatest tendency toward curvature of the bufling disk; and as an instance the rear face of the disk 8 is curved so that it has a gradually bulging thickness 28 toward its outer periphery, with this bulging thickness in turn gradually merging into the thickness of the channeled annulus l.

The counterweight is such that the center of gravity of the entire. rotating structure, longitudinally of itsaxis of rotation,` approximately coincides with the plane I4,i. e. `the normal plane of the backing I; Consequently, vwhen the bufling disk Vis rotated `there is no tendency of its backing I to distort from its normal plane I4, andthe buing surface of the disk thus defines the paral.. lel plane 4 and is thus adapted for uniform bufng `Contact and consequent uniform wear throughout its, area.

In, additionror inV lieu of counterweighting the disk 8 for insuring rotation ofthe puffing disk with its backing I ina plane perpendicular to the axisjof rotation, the disk 8 may be arranged-so that, when rotated it tends to distort by curving `at its outer periphery toward the plane I5 as shown at I'I (Fig. 4), with this tendency just sufficient to counteract any tendency (as previously described) of the backing I to curve in the opposite direction as shown at I3. These tendencies thus oppose one another for maintaining the backing I in the plane I4, thereby maintaining the bufiing surface in the plane 4 for uniform wear throughout its area.

As an instance and las shown at Fig. 4, the rubber disk 8 vmay be reinforced in a plane adjacent that face of the diskwhich engages the backing I, in spaced relation fromits rear face which defines its thickened portion 2t. This reinforcement is shown as fabric reinforcement 30. When the structure is rotated, that portion of the disc 8 which is adjacent its face which engages the backing I is thus held against radial stretch by the reinforcement 30, while the rear portion of the disk, i. e. its thickened portion 2G, is subject to radial stretch responsive to centrifugal force, thereby tending tocurve the disk 8 as shown at I1. But this tendency is opposed by the tendency of the backing I to curve as shown Vat I6, as will result from the plane I seeking alinement with the plane I4. These tendencies thus counteract one another, so as to maintain the backing I in the plane I4.

I claim:

1. In a rotatable buing disk, a backing having a pile projecting from its face and forming a, buffing surface transverse to the axis of rotation, and means for counterweighting that face of the backing which is opposite its projecting pile, so that the center of gravity of the disk, longitudinally of its axis of rotation, is in the plane of the backing.

2. In a rotatable bufiing disk, a backing having a pile projecting from its face and forming a buffing surface transverse to the axis of rotation, and an auxiliary disc fixed for rotation with the bufng disc and counterweighting that face of the backing which is opposite its projecting pile, so that the center of gravity of the dependently rotatable disks, longitudinally of the axis of rotation, is in the plane of the backing of the buffing disk.

3. In a rotatable bufng disk, a backing having a, pile projecting from its face and forming a buffing surface transverse to the axis of rotation, that.

portion of the pile which is adjacent the outer periphery of the backing being bent toward the axis of the disk and then projecting outwardly from the face of the backing, an auxiliary disk adapted to overlie the face of the backing which is opposite its projecting pile, and a clamping annulus at the periphery of the auxiliary disk adapted to engage the periphery of the buing disk for clamping said portion of the pile to the backing at the junction of its bent and outwardly projecting portions, for bracing the remainder of the pile against radial distortion responsive to rotation of the disk, so as to maintain the bufng surface in a plane substantially perpendicular to the axis of rotation for uniform wear throughout its area, the auxiliary disc being fixed for rotation with the bufling disc and counterweighting that face of the backing which is opposite its projecting pile, so that the center of gravity of the dependently rotatable disks, longitudinally of the axis of rotation, is in the plane of the backing of the buffing disk.

4. In a rotatable buiiing disk, a backing having a pile projecting from its face and forming a buiing surface transverse to the axis of rotation, an auxiliary disk adapted to overlie that face of the backing which is opposite its projecting pile, the auxiliary disk being adapted for radial stretch responsive to centrifugal force, and means for reinforcing and preventing radial stretch of that portion of the auxiliary disk which is proximate the backing of the bung disc, whereby radial stretch of the remaining portion of the auxiliary disk tends to curve the outer periphery of the auxiliary disk toward the backing of the bufng disc.

5. In a rotatable buing disk, a backing having a pile projecting from its face and forming a buiflng surface transverse to the axis of rotation. that portion of the pile which is adjacent the outer periphery of the backing being bent to- Ward the axis of the disk and then projecting outwardly from the face of the backing, an auxiliary disk adapted to overlie the face of the backing which is opposite its projecting pile, ya clamping annulus at the periphery of the auxiliary disk adapted to engage the periphery of the buing disk for clamping said portion of the pile to the backing at the junction of its bent and outwardly projecting portions, for bracing the remainder of the pile against radial distortion responsive to rotation of the disc, so as to maintain the buing surface in a. plane substantially parallel to the backing of the buffing disk. the auxiliary disk being adapted for radial stretch responsive to centrifugal force, and means for reinforcing and preventing radial stretch of that portion of the auxiliary disk which is proximate the backing of the bumng disk, whereby radial stretch of the remaining portion of the auxiliary disc tends to curve the outer periphery of the auxiliary disk toward the backing of the bufng disk.

6. .In a rotatable buing disk, a backing having a pile projecting from its face and forming a buffng surface transverse to the axis of rotation. that portion of the pile which isv adjacent the outer periphery of the backing being bent toward the axis of the disk and then projecting outwardly from the face of the backing, an auxiliary disk adapted to overlie the face of the backing which is opposite its projecting pile, a clamping annulus at the periphery of the auxiliary disk adapted to engage the periphery of the bufling disk for clamping said portion of the pile to the backing at the ljunction of its bent and outwardly projecting portions, for bracing the remainder of the pile against radial distortion responsive to rotation of the disc, so as to maintain the buiiing surface in a plane substantially parallel to the backing of the buliing disc, the auxiliary disc being fixed for rotation with the buffmg disc and counterweighting that face of the backing which is opposite its projecting pile, so that the center of gravity of the dependently rotatable disks, longitudinally of the axis oi rotation, is shifted toward the plane of the backing -of the buing disk, the auxiliary disk being adapted for radial stretch responsive to centrifugal force, and means for reinforcing and preventing radial stretch of that portion of the auxiliary disk which is proximate the backing of the buiiing disk, whereby radial stretch of the remaining portion of the auxiliary disc tends to curve the outer periphery of the auxiliary disc toward the backing of the buing disc.

FRANK W. LIVERMONT. 

